Transcript MRI- Magnetic resonance imaging

By Prashil Patel
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Test that uses a magnetic field and pulses of
radio wave energy to make pictures of organs
and structures inside the body.
Body is placed inside a special machine that
contains a strong magnet.
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An MRI is similar to a (CT)
scanner in that it produces
cross-sectional images of the
body
MRI uses a strong magnetic
field and radio waves to
produce very clear and detailed
computerized images of the
inside of the body.
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Felix Bloch of Stanford University and Edward
Purcell of Harvard University made the first
successful nuclear magnetic resonance, NMR,
experiment to study chemical compounds in
1946
NMR creates magnetic fields and radio waves
cause atoms to give off tiny radio signals.
In the early 1980s, the first "human" magnetic
resonance imaging (MRI) scanners became
available, producing images of the inside of the
body.
Used to find problems such as
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Tumors
Bleeding
Injury
Blood vessel diseases
Infection
MRI scan can be done for
Head
Chest
Blood vessels
Abdomen and pelvis
Bones and joins
spine
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T1 MRI
T1 MRI is known as Spin-lattice relaxation time
It differentiates fat from water - with water
darker and fat brighter
T1-weighted MRI is best for looking at brain
structures
The strength of the magnets used in T1 are in
the 0.5-tesla to 2.0 -tesla range
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T2 MRI
T2 MRI is known as spin-spin relaxation time
Like T1 MRI, T2 also differentiates fat from
water, but fat shows darker, and water lighter
T2 is better for looking at non-enhancing brain
lesions
The strength of the magnets used in T2 are in
the 0.5-tesla to 2.0 -tesla range
T1 Image
T1 MRI Scan
1.5 Telsa
T2Image
T2 MRI Scan
1.5 Telsa
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Concentration of protons in the tissue in the
form of water and macromolecules.(Far,
Protein, etc)
Utilizes the difference in proton densities of
two materials when T1 and T2 characteristics
are similar.
T1-Weighted
T2-weighted
Proton
Density
Weighted
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Because of the small space given, some patients
experience claustrophobia have difficulty in
cooperating during the study.
Some obese patients cannot be examined
Patients with pacemakers and certain
ferromagnetic appliances cannot be studied
MRI equipment is expensive to purchase,
maintain, and operate
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Very small scanners for imaging specific body
parts are being developed
Researchers at the University of Zurich, has
recently demonstrated a novel way of enticing
hydrogen atoms to produce images. This will
produce images of larger portions of the body
and at the same time free up some space
around the patient.
The usage of the stronger magnets, 7 tesla will
produce high definition images but has not yet
been approved due to high magnetic field.
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Department of Health and Human Services
University of Zurich article
Discovery Fit & Health
Pubmed.gov
http://www.medhelp.org
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